Dynamoelectric machine stator construction



y 1954 J. H. STAAK DYNAMOELECTRIC MACHINE STATOR CONSTRUCTION Filed March 23, 1953 Inventor-z J lius H. Ztaak, b g His Attorngy Patented July 13, 1954 DYNAMOELECTRIC MACHINE STATOR CONSTRUCTION Julius H. Steak, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application March 23, 1953, Serial No. 343,883

5 Claims.

This invention relates to the stator construction of dynamoelectric machines and more particularly to the mechanical assembly of small motors.

In the design of certain small dynamoelectric machines such a computer motors, it has been found diflicult to control the length of the air gap between the rotor and field structure and the concentricity of the rotor within stator bore without the necessity for performing expensive and time consuming machining operations. It is therefore desirable to provide a construction for a small dynamoelectrlc machine wherein the air gap length and concentricity can be held to very close tolerances without the accompanying requirement for excessive machining and hand matching of components.

It is therefore an object of this invention to provide an improved dynamoelectric machine construction incorporating the desirable features set forth above.

Further objects and advantages of this invention will become apparent and the invention will be better understood by reference to the following description and the accompanying drawing, and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In accordance with this invention, a pair of spaced apart end flanges are provided respectively having bearings mounted therein. A shaft is rotatably seated in the bearings with a rotor mounted thereon. Each of the two end flanges has its outer periphery machined to the desired diameter of the stator bore and a plurality of elongated pole piece members are provided each having its ends respectively secured to the outer surfaces of the end flange members thereby bridging the end flanges and defining a bore for the rotor member. Poles are respectively formed on the outer surfaces of the pole piece members and field coils are respectively arranged thereon. A yoke member surrounds the poles to complete the magnetic circuit. One of members may have an annular portion having a larger diameter to which an enclosing case is secured. A brush holder mechanism may be arranged within the pole piece members with brush holder tubes projecting therebetween.

In the drawing,

Fig. 1 is a side elevational view, partly in section, illustrating the improved dynamoelectric machine construction of this invention; and

Fig. 2 is a fragmentary view in perspective furthe end flange ther illustrating the improved construction of this invention.

Referring now to Fig. 1, there is shown a dynamoelectric machine generally identified as I, such as a small direct current computer motor for aircraft use. A first end flange member 2 is provided having a bore 3 in which a suitable antifriction bearing 4 is arranged. A second end flange member 5 is also provided having a bore 6 in which a second anti-friction bearing "I is arranged. A shaft 8 is rotatably seated in bearings 4 and I and has armature member 9 mounted thereon. It will be seen that the outer race I a of bearing 4 is seated against a shoulder II formed in bore 3 of end shield 2 and that shaft 8 has a shoulder I2 seated against inner race I3 of bearing 4. Inner race I 4 of bearing I is likewise seated against shoulder I5 of shaft 8 and axial end play of the shaft is then controlled by plug I 6 threadingly seated in bore 6 of end shield 5 and bearing against outer race I! of bearing 1.

In order to provide for mounting the field poles of machine I, the outer periphery I 8 of end flange 2 is machined concentric with bore 3 to the desired diameter of the stator bore, i. e., equivalent to the diameter of armature 9 plus twice the desired air gap length. End flange 5 is provided with an inner portion I 9 having its outer periphery 20 similarly machined concentric with bore 6 to the same diameter as the outer periphery I8 of end flange 2. Four elongated pole piece members 21 are provided each having its one end 22 secured to the outer surface I8 of end flange 2 in any suitable manner, as by screws 23, and having it other end 24 secured to the outer surface 28 of inner portion I9 of end flange 5 in any suitable manner, as by screws 25. Since the outer peripheries I8 and 20 of end flange 2 and inner portion I9 of end flange 5, respectively, have been 1 machined to the desired stator bore diameter, it

will now be apparent that pole piece members 2| by bridging end flange 2 and inner portion I9 of end flange 5 define the bore for armature a and automatically establish the proper air gap and concentricity. Pole piece members 2| are preferably skewed or longitudinally spiralled as best shown in Fig. 2.

Suitable poles 26 are formed on pole pieces 2| and field coils 21 are arranged thereon. After assembly of the devices thus far described, outer yoke member 28 is arranged around poles 26 and may be secured thereto in any suitable manner, as by screws 29, or in the alternative may he slipped snugly or shrunk over the poles 26 to complete the magnetic circuit.

In order to provide a brush holder assembly, a split ring 36 of suitable insulating material is arranged within pole piece members 2| surrounding commutator 3| with suitable brush holder tubes 32 being mounted therein and projecting between pole piece members 2!. Brush holder ring 3% is expanded into tight engagement with pole piece members 2! by any suitable expanding means, such as a split tube. This type or" brush holder is more fully shown and described in my copending application Serial No. 269,278, filed January 31, 1952, and assigned to the assignee of this application.

In order to provide an enclosing case or housing, end shield 5 is provided with an annular portion 33 having a larger diameter than the diameter of the inner portion i9. A drawn cuter case member 34 is arranged over yoke member 23 and engaging outer portion 33 of end flange member 5 in any suitable manner, as by the rabbet connection shown at 35.

t will now be readily seen that this invention provides a simple construction for small dyna'mo electric machines wherein the air gap length and coneentricity are assured with a minimum of machining.

While I have shown and described a particular embodiment of this invention, further modifications and improvements will occur to those skilled in the art, I desire that it be understood therefore that this invention is not limited to the form shown and I intend in th appended claims to cover all modifications which do not depart from the spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a dynamoelectric machine, a stator asrib-1y comprising a pair oi spaced apart end respectively having bearings mounted a plurality of elongated equally spaced ii idinally disposed pole 1 we memer respectively secured to said end flanges thereby bridging the and defining a bore for the rotor member of said machine, each of s2 pole piece members having a pole formed on its outer suriace, field coils respectively arranged on sail poles, and a yoke member surrounding said poles.

2. in a dynamoelectric machine, a stator assembly comprising a pair of spaced apart end fiiges each having a cylindrical outer surface, each or" said end flanges having a bearing mounted therein, a plurality of equally spaced longitudinally disposed pole piece members, each of said pole piece members being curved transverse-1y to conform to said outer surfaces or said end fianges and having its ends respectively secured thereto thereby bridging the same and defining a bore for the rotor member of said machine, each of said pole piece members having a pole formed on its outer surface, field coils respectively arranged on said poles, and a yoke member surrounding said poles.

3. In a dynamoelectric machine, a stator assembly comprising a pair of spaced apart end flanges each having a cylindrical outer surface, each of said end flanges having a bearing mounted therein, a plurality of equally spaced apart longitudinally disposed pole piece members, each of said pole piece members being curved transversely to conform to said outer surfaces of said end flanges and having its ends respectively secured thereto thereby bridging the same and defining a bore for the rotor member of said machine, said pole piece members having a longitud nal spiral, each of said pole piece members having a pole formed on its outer surface, field coils respectively arranged on said poles, and a yoke member surrounding said poles.

l. In a dynamoelectric machine, a stator assembly comprising a pair of spaced apart end flanges respectively having bearings mounted therein, a plurality of equally spaced apart 1ongitudinally disposed pole piece members, each of said pole piece members having its ends respectively secured to said end flanges thereby bridging the same and defining a bore for the rotor member of said machine, each of said pole piece members having a pole formed on its outer sur face, field coils respectively arranged on said poles, yoke members surrounding poles, and a brush holder assembly mounted wit in said pole piece members with brush holder tubes proiecting therebetween.

5. In a dynamoelectric machine, a stator assembly comprising a first end flange having a cylindrical outer surface, a second end flange spaced from said first end flan e having a first portion with a cylindrical outer surface oi the same diameter as said first end flange and a second portion with a cylindrical outer surface of larger diameter than said first portion, each of said end flanges having a bearing mounted therein, a plurality of equally spaced apart longitudinally disposed pole piece members, each of said pole piece members being curved transversely to conform to said outer surfaces said first end flange and said first portion of said second end flange and having its ends respectively secured thereto thereby bridging the same and defining a bore for the rotor member of machine, each of said pole piece members having a pole formed on its outer surface, field coils respectively arranged on said poles, a yoke member surrounding said poles, and an outer enclosing shell member embracing said yoke member engaging said second portion of said s-ccnd end flange.

References cited in the file of this patent UNITED STATES PAinNTS Bryan Dec. 18, 

